The present invention relates to a new and improved construction of a reflector antenna for applications in outer space and to a method of fabricating such reflector antenna.
In its more particular aspects, the present invention relates not only to the reflector antenna itself, but also to an improved method for constructing and deploying the reflector antenna. The reflector antenna specifically comprises a parabolically-shaped reflector antenna comprising an unfolding or deployable laminated-surface structure, an inflatable radome which forms a shroud-like body structure, an antenna reflector and a rigidizing member or annulus, such as a torus or toroidal support member.
The reflector antenna fabrication method of the present invention aims at providing a reflector antenna construction whose reflector forms together with a radome a cavity, stabilized by means of a tubular rigidizable torus.
In other words, the method aspects of the present invention relate to a method for fabricating an inflatable reflector antenna for deployment in outer space and comprises the steps of fabricating an antenna reflector, an antenna radome and a stabilizing annulus from a textile laminate, wherein the textile laminate for at least the antenna reflector and the antenna radome is a textile laminate impregnated with a setting component. The textile laminate for the antenna radome more specifically is a textile laminate transparent to at least a portion of the electromagnetic spectrum of radiant energy. Moreover, a material layer reflective of at least such portion of the electromagnetic spectrum of radiant energy is applied to an inner side of the antenna reflector.
The method of the present invention for deploying a reflector antenna in outer space comprises the steps of transporting beyond the atmosphere an antenna package comprising an antenna feed mast and an inflatable envelope made of a textile laminate and wrapped around the antenna feed mast in a series of folded pleats ready for deployment, wherein the inflatable envelope comprises an antenna reflector, an antenna radome and a stabilizing annulus, and the textile laminate is impregnated with a setting component, such as a setting resin for at least the antenna reflector and the antenna radome.
The reflector antenna of the present invention is for deployment in outer space and comprises an antenna feed mast having a first end provided with an interface socket for attachment to a transport vehicle and a second end remote from the first end and provided with a feed head for the reflector antenna. The reflector antenna further comprises an antenna reflector, an antenna radome and a stabilizing annulus conjointly defining an inflatable envelope. The inflatable envelope has an initial folded state in which the inflatable envelope is wrapped around the antenna feed mast to form a compact antenna package for transport into outer space and a terminal deployed state in which the inflatable envelope is inflated to form a desired spatial configuration of the reflector antenna defining a focal point of the antenna reflector and in which the feed head is at the focal point.
For reflector antennas of the aforementioned construction, e.g., for applications in outer space, there exist additional stringent requirements, such as precise dimensional stability and accuracy of the antenna structure in addition to special requirements which are imposed by transport conditions to an orbit in space vehicles, i.e., minimum weight and compactly folded packaged condition.
In common practice, antennas for applications in outer space are of mechanical construction, comprising ribs and/or panels with numerous individual components, such as hinges, supports, springs, tie ropes, brake systems for controlled deployment and many more. This involves intricate construction schemes and furthermore, due to the large number of individual components, requires compromises between reflector dimensional accuracy and/or reliability.
Problems involving such mechanically unfoldable antennas are further described in an article by W. Schafer:
Stand der Technik auf dem Gebiet grosserer, entfaltbarer Parabolantennen-Strukturen fur Raumfluggerate (cf. Flugwissenschaftliche Weltraumforschung Apr. 4, 1980, No. 5).
There has long been known in the art a gas pressure deployable and stabilizable, i.e., inflatable, parabolic antenna construction displaying relatively low weight and low storage volume, together with large operating diameter and especially high dimensional reflector accuracy (cf. American Institute of Aeronautics and Astronautics, January, 1980). Such an antenna, however, is endangered by meteorites, thus exhibiting a short life expectancy and requiring the transport of gas supplies for replenishing and maintaining gas pressure within the antenna cavity, i.e., to replace losses of gas caused by meteorite punctures and leaks along the seams.